Diesel engine fuel variable injection timing, sequence and high pressure constant pressure injection device

Abstract

The invention discloses a device for variable fuel injection timing, sequence and high-pressure constant-pressure injection of diesel engine fuel, comprising a high-pressure oil pump and a high-pressure oil pump seat, wherein a plunger pair consisting of a plunger sleeve and a plunger is installed in the high-pressure oil pump, an oil outlet joint is installed at the upper end of the high-pressure oil pump, an oil outlet valve is installed in the oil outlet joint, a power piston cylinder and a hydraulic cylinder are processed in the high-pressure oil pump seat, an injection pushing mechanism is installed in the power piston cylinder, and the injection pushing mechanism comprises a power piston, and the upper end of the plug rod of the power piston is connected with the lower end of the plunger; an oil inlet pipe and an oil return pipe for providing hydraulic oil to the power piston through a reversing valve are installed on the high-pressure oil pump seat, and a hydraulic piston is arranged in the hydraulic cylinder; oil inlet and outlet holes are opened on the hydraulic cylinder, and the hydraulic piston is meshed with an injection timing adjustment sleeve rack, and the injection timing adjustment sleeve rack pulls the hydraulic piston to rotate so that the injection timing is automatically adjusted with the speed of the diesel engine; and an annular injection groove is processed on the head of the plunger.

Description

Technical Field

[0001] The invention relates to the technical field of fuel injection in an internal combustion engine, in particular to a diesel engine fuel injection device with variable injection timing, sequence and high pressure constant pressure. Background Art

[0002] At present, the fuel injection system of diesel engines has the following three structures which are more commonly used: cam push rod mechanism, high pressure common rail injection system and electromagnetic control injection system.

[0003] 1. The cam push rod mechanism is used to push the roller of the push rod to drive the push rod up and down through the rotation of the cam, so that the high-pressure oil pump can spray fuel. The structure using the cam push rod mechanism has the following main disadvantages:

[0004] 1. The roller of the cam follower is in line contact. Due to the limitation of the pressure bearing capacity of the metal surface, the roller cannot increase too fast, which makes it difficult to increase the injection speed of the high-pressure oil pump and the fuel injection rate;

[0005] 2. When the diesel engine is running at low speed, the injection speed of the high-pressure oil pump and the fuel injection rate are further reduced, the fuel atomization effect is deteriorated, and a large amount of carbon deposits are generated on the piston and combustion chamber, resulting in rapid wear of the cylinder liner;

[0006] 3. Due to poor atomization, the fuel consumption rate increases sharply;

[0007] 4. Since the injection angle cannot be changed with the speed, the diesel engine will spray at too large an angle at low speed, resulting in a large increase in NOx and particulate emissions, causing environmental pollution.

[0008] Second, the high-pressure common rail injection system is used, that is, the fuel is generated at high pressure through a high-pressure oil pump and enters the high-pressure fuel main pipe. The high-pressure fuel is injected through the high-speed solenoid valve control. The high-pressure common rail system mainly has the following problems:

[0009] 1. Based on the current usage, the structure of the high-pressure common rail injection system is not yet mature. Due to the pressure and sealing limitations of the electromagnetic reversing valve, the fuel pressure cannot be increased to more than 180MPa. In other words, the start-up pressure of the injector is still difficult to reach 60MPa, and the atomization of the fuel has not been further improved;

[0010] 2. It is difficult for the high-pressure common rail injection system to burn heavy oil on medium- and high-speed diesel engines. The circulation system of heavy oil is: high-pressure pump-fuel inlet manifold-fuel injection pump-heating unit-high-pressure pump. This circulation system is to ensure the constant temperature of heavy oil to ensure that the viscosity of heavy oil does not exceed the requirements. For 7000-second heavy oil, the heating temperature is required to reach above 140°C. Since heavy oil needs to be circulated and pressurized, it consumes too much energy. At present, the wide application of high-pressure common rail systems on medium- and high-speed diesel engines is subject to certain restrictions.

[0011] 3. Electromagnetic control injection system, that is, the high-pressure fuel generated by the cam push rod and the high-pressure fuel pump is controlled by the solenoid valve, and the injection angle is changed according to different speeds, so that the fuel can be injected at the best angle. The main disadvantages of the electromagnetic control injection system are:

[0012] Although electromagnetically controlled injection can change the injection angle, making combustion more perfect during diesel engine operation and effectively reducing NOx emissions, the electronic injection system still uses a cam plus a high-pressure oil pump. The injection pressure is not increased, and the atomization effect is still not ideal when the diesel engine is running at low speed. Summary of the invention

[0013] The technical problem to be solved by the present invention is to provide a diesel engine fuel variable injection timing, sequence and high-pressure constant-pressure injection device with high start-injection oil pressure, stable pressure, low fuel consumption, and the ability to automatically change the injection angle as the diesel engine speed changes, in response to the above-mentioned existing technical status.

[0014] The technical solution adopted by the present invention to solve the above technical problems is:

[0015] A diesel engine fuel variable injection timing, sequence and high-pressure constant-pressure injection device comprises a high-pressure oil pump seat with a high-pressure oil pump installed on the upper end, a plunger pair consisting of a plunger sleeve and a plunger installed in the high-pressure oil pump, an oil outlet joint installed on the upper end of the high-pressure oil pump, an oil outlet valve for cooperating with the plunger pair to start the oil injection is installed in the oil outlet joint, a power piston cylinder and a hydraulic cylinder are processed in the upper and lower structures of the high-pressure oil pump seat, an injection push mechanism for driving the plunger to move up and down by hydraulic oil is installed in the power piston cylinder, the injection push mechanism comprises a power piston whose lower end surface can have the same hydraulic thrust at different speeds of the diesel engine to realize high-pressure constant-pressure injection, and the upper end of the plug rod of the power piston is connected to the lower end of the plunger; a power piston driven by a reversing valve is installed on the high-pressure oil pump seat The up and down movement of the force piston provides an oil inlet pipe and an oil return pipe for the hydraulic oil. A hydraulic piston is slidably arranged in the hydraulic cylinder. The hydraulic piston and the hydraulic cylinder together constitute a power oil pump that uses hydraulic oil to push the valve core of the reversing valve to move left and right to achieve the change of the oil supply direction; the hydraulic piston moves up and down under the push of the diesel engine cam; the hydraulic cylinder is provided with hydraulic oil inlet and outlet holes, and the hydraulic piston is engaged with an injection timing adjustment sleeve rack that is connected to the diesel engine speed adjustment mechanism and moves synchronously with the diesel engine speed adjustment mechanism. The injection timing adjustment sleeve rack changes the action time of the reversing valve by pulling the hydraulic piston to rotate and changing the time of covering the inlet and outlet holes, so that the injection timing is automatically adjusted with the diesel engine speed; the head of the plunger is processed with an annular injection groove for realizing the sequential injection of high-pressure fuel in batches.

[0016] To optimize the above technical solutions, the specific measures taken also include:

[0017] The above-mentioned power oil pump, reversing valve and injection timing adjustment sleeve rack together constitute the injection timing adjustment and injection control mechanism; the hydraulic piston is composed of a tappet, a roller, a roller pin, an injection timing adjustment gear sleeve, an oil storage piston and a return spring; the roller pin is inserted into the pin hole at the lower end of the tappet, and the roller is rotatably mounted on the roller pin, and the roller is in rolling contact with the cam of the diesel engine; the oil storage piston is slidably arranged at the upper port of the oil storage cavity processed by the tappet, and the return spring is elastically pressed into the oil storage cavity through the oil storage piston; the injection timing adjustment gear sleeve can be rotatably mounted on the tappet, and the outer surface of the injection timing adjustment gear sleeve is processed with a gear meshing with the injection timing adjustment sleeve rack.

[0018] The above-mentioned injection timing adjustment gear sleeve is machined with an oblique cut of the gear sleeve for changing the time of covering the inlet and outlet oil holes. The relative position of the oblique cut of the gear sleeve and the inlet and outlet oil holes on the hydraulic cylinder changes with the rotation of the injection timing adjustment gear sleeve; a pressure oil channel connected to the hydraulic cylinder for pushing the valve core of the reversing valve is machined in the high-pressure oil pump seat.

[0019] A plug body is formed at the bottom of the plug rod of the above-mentioned power piston, and a sealing annular groove is processed on the plug body, in which a sealing ring is installed; the plug body divides the power piston cylinder into a rod chamber located above the plug body and a rodless chamber located below the plug body; the oil inlet pipe includes an upper oil inlet pipe of the power piston connected to the rodless chamber of the power piston cylinder through a reversing valve and a lower oil inlet pipe of the power piston connected to the rod chamber of the power piston cylinder through a reversing valve.

[0020] The power piston and plunger are connected to each other so as to be relatively rotatable. The upper end of the plug rod of the power piston is processed with an annular snap-in groove with a radial snap-in entrance, and the lower end of the plunger is formed with an annular snap-in protrusion that can be axially snapped into the annular snap-in groove to prevent it from slipping off.

[0021] The outer peripheral surface of the plunger sleeve is formed with an annular fuel channel connected to the fuel supply pipe, and the annular fuel channel is processed with a fuel inlet hole radially connecting the annular fuel channel and the sleeve cavity of the plunger sleeve; the plunger is slidably arranged in the sleeve cavity of the plunger sleeve.

[0022] The head of the above-mentioned plunger is processed with two annular injection grooves that can enable high-pressure fuel to be injected three times in sequence, and a lower annular oil groove located below the annular injection grooves; the two annular oil grooves include a first annular oil groove located above and a second annular oil groove located below, and the lower annular oil groove is located below the second annular oil groove; a beveled oil groove connected to the top surface of the plunger is formed on the head of the plunger; the first annular oil groove, the second annular oil groove and the lower annular oil groove are all connected to the beveled oil groove.

[0023] A plunger rack is formed at the lower part of the plunger, and a high-pressure oil pump oil regulating rack is installed on the high-pressure oil pump, which meshes with the plunger rack and changes the position of the beveled oil groove and the fuel inlet hole by pulling the plunger to rotate.

[0024] Compared with the prior art, the plunger of the present invention is pushed by the power piston to reciprocate, and the hydraulic oil supply of the power piston is controlled by the power oil pump and the reversing valve composed of the hydraulic piston and the hydraulic cylinder, and the hydraulic piston is pushed up and down by the diesel engine cam; the hydraulic piston is meshed with an injection timing adjustment sleeve rack, and the injection timing adjustment sleeve rack changes the time of covering the oil inlet and outlet holes by pulling the hydraulic piston to rotate to change the action time of the reversing valve so that the injection timing is automatically adjusted with the speed of the diesel engine; the head of the plunger is processed with two annular injection grooves for realizing three-time sequential injection of high-pressure oil. The present invention can automatically change the injection timing, that is, the injection angle, with the change of the diesel engine speed, reduce the injection advance angle when the diesel engine speed is low, and increase the injection advance angle when the diesel engine speed is high, so as to ensure that the diesel engine injects at the most appropriate advance angle at different speeds and improve the combustion process.

[0025] The present invention adopts sequential injection, changing the original one-time fuel injection into three injections, so that the fuel is injected into different areas, and the fuel and compressed air are mixed more fully; the fuel injected into the cylinder is burned three times, and the combustion pressure in the cylinder increases in stages, which can also effectively reduce the combustion temperature and combustion pressure, reduce NOx emissions, and meet the requirements of IMO emission regulations. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a three-dimensional structural schematic diagram of the present invention;

[0027] Figure 2 It is a schematic diagram of the main structure of the present invention;

[0028] Figure 3 yes Figure 2 BB section structure diagram;

[0029] Figure 4 yes Figure 2 AA section structure diagram;

[0030] Figure 5 yes Figure 3 The local enlarged schematic diagram of point Ⅰ in the middle;

[0031] Figure 6 It is a structural schematic diagram of the hydraulic piston of the present invention;

[0032] Figure 7 yes Figure 6 CC section structure diagram;

[0033] Figure 8 It is a schematic diagram of the structure of the plunger pair of the present invention;

[0034] Fig. 9 yes Figure 8 DD section structure diagram;

[0035] Fig.10 It is a three-dimensional structural schematic diagram of the connection between the power piston and the plunger of the present invention;

[0036] Fig.11 It is a schematic diagram of the structure of the connection between the power piston and the plunger of the present invention;

[0037] Fig.12 It is a schematic structural diagram of the power piston of the present invention;

[0038] Fig.13 It is a schematic diagram of the structure of the plunger of the present invention;

[0039] Fig.14 This is a position state diagram of the plunger of the present invention when the first oil injection begins;

[0040] Fig.15This is a position state diagram of the plunger of the present invention when the first oil injection ends;

[0041] Fig.16 This is a position state diagram of the plunger of the present invention when the second fuel injection starts;

[0042] Fig.17 This is a position state diagram of the plunger of the present invention when the second oil injection ends;

[0043] Fig.18 This is a position state diagram of the plunger of the present invention when the third fuel injection starts;

[0044] Fig.19 It is a position state diagram of the plunger of the present invention at the end of the third oil injection.

[0045] Figures 1 to 19 1 is a schematic diagram of the structure of the present invention, wherein the reference numerals are: oil outlet connector T, oil outlet valve F, overflow valve F1, pressure reducing valve F2, pressure stabilizing valve F3, sealing ring M, valve core X, high-pressure oil pump seat 1, power piston cylinder 1a, hydraulic cylinder 1b, oil inlet and outlet holes 1c, pressure oil channel 1d, high-pressure oil pump 2, plunger sleeve 31, annular fuel channel 31a, fuel inlet hole 31b, plunger 32, first annular injection groove 32a, second annular injection groove 32b, lower annular oil groove 32c, oblique cut oil groove 32d, annular shaped snap-in protrusion 321, plunger rack 322, power piston 4, sealing annular groove 4a, plug rod 41, annular snap-in groove 41a, plug body 42, hydraulic piston 5, oil storage chamber 5a, tappet 51, roller 52, roller pin 53, injection timing adjustment gear sleeve 54, gear 54a, gear sleeve oblique cut 54b, oil storage piston 55, return spring 56, injection timing adjustment sleeve rack 6, power piston upper oil inlet pipe 71, power piston lower oil inlet pipe 72, oil return pipe 8, high-pressure oil pump oil regulation rack 9. DETAILED DESCRIPTION

[0046] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0047] Figures 1 to 19The structure diagram of the present invention is shown in the figure. As shown in the figure, the present invention discloses a diesel engine fuel variable injection timing, sequence and high-pressure constant pressure injection device, the device includes a high-pressure oil pump 2 for spraying high-pressure fuel and a high-pressure oil pump seat 1 for installing the high-pressure oil pump 2. The high-pressure oil pump seat 1 is processed with a power piston cylinder 1a and a hydraulic cylinder 1b in an upper and lower structure. The power piston cylinder 1a has an upper opening and the hydraulic cylinder 1b has a lower opening; the high-pressure oil pump 2 is installed at the upper end of the high-pressure oil pump seat 1. A plunger cavity for installing a plunger pair is processed in the high-pressure oil pump 2, and a plunger pair consisting of a plunger sleeve 31 and a plunger 32 is installed in the plunger cavity. The plunger cavity is coaxially corresponding to the power piston cylinder 1a, and a power piston cylinder cover is installed at the opening of the power piston cylinder 1a so that the power piston cylinder 1a forms a sealed hydraulic cylinder body. An oil outlet joint T with a connecting thread at the front end is installed at the upper end of the high-pressure oil pump 2, and an oil outlet valve F is installed in the oil outlet joint T to cooperate with the plunger pair to start the oil injection at a set pressure.

[0048] The key point of the present invention is that an oil injection driving mechanism driven by hydraulic oil is installed in the power piston cylinder 1a, and the oil injection driving mechanism drives the plunger 32 to work, thereby realizing the up and down reciprocating motion of the plunger 32. The oil injection driving mechanism of the present invention is a power piston 4, which is composed of a plug rod 41 and a plug body 42 integrally formed at the bottom of the plug rod 41. The plug rod 41 slides through the power piston cylinder cover in a liquid-tight manner, and its upper end is connected to the lower end of the plunger 32. Figure 3 , Figure 5 and Fig.12 As shown, the diameter of the plug body 42 is larger than the diameter of the plug rod 41, and a sealing annular groove 4a is machined on the plug body 42 along the entire circumference, and a sealing ring M is installed in the sealing annular groove 4a for sealing. The sealing ring M forms a liquid seal between the outer peripheral wall of the plug body 42 and the inner wall of the power piston cylinder 1a, so that the plug body 42 can divide the power piston cylinder 1a into a rod chamber located above the plug body 42 and a rodless chamber located below the plug body 42. An oil inlet pipe, an oil return pipe 8 and a reversing valve (the reversing valve is not marked in the various figures of the present invention) are installed on the high-pressure oil pump seat 1. The oil inlet pipe is connected to the reversing valve through an oil inlet branch pipe, and the oil return pipe 8 is connected to the reversing valve through an oil return branch pipe. The rod chamber and the rodless chamber of the power piston cylinder 1a are connected to the reversing valve through a pipeline machined inside the high-pressure oil pump seat 1. In other words, the up and down movement of the power piston 4 is controlled by the reversing valve, and the oil inlet pipe and the oil return pipe 8 provide hydraulic oil to the power piston 4. The present invention Figure 1 , Figure 3 and Figure 4 It can be seen that the oil inlet pipe includes an upper power piston oil inlet pipe 71 connected to the rodless chamber of the power piston cylinder 1a via a reversing valve, and a lower power piston oil inlet pipe 72 connected to the rod chamber of the power piston cylinder 1a via a reversing valve.

[0049] A hydraulic piston 5 is slidably provided in the hydraulic cylinder 1b of the present invention. The hydraulic piston 5 and the hydraulic cylinder 1b together constitute a power oil pump that uses hydraulic oil to push the valve core X of the reversing valve to move. The present invention uses the hydraulic oil discharged by the power oil pump composed of the hydraulic piston 5 and the hydraulic cylinder 1b to push the reversing valve to move, thereby controlling the inflow and outflow of the hydraulic oil in the rodless chamber and the rod chamber of the power piston cylinder 1a, and realizing the change of the oil supply direction. The hydraulic piston 5 moves up and down along the diesel engine cam; the lower end of the hydraulic piston 5 is in elastic rolling contact with the diesel engine cam and moves along the cam. The hydraulic cylinder 1b is provided with a hydraulic oil inlet and outlet hole 1c, and the hydraulic piston 5 is meshed with an injection timing adjustment sleeve rack 6. The injection timing adjustment sleeve rack 6 is connected to the diesel engine speed adjustment mechanism and moves synchronously with the diesel engine speed adjustment mechanism. The diesel engine speed adjustment mechanism drives the injection timing adjustment sleeve rack 6 to move linearly, and the injection timing adjustment sleeve rack 6 can pull the hydraulic piston 5 to rotate during the linear motion. The hydraulic piston 5 can change the time of covering the inlet and outlet holes 1c by rotating. Only after the oil inlet and outlet holes 1c are blocked, can the power oil pump build up pressure, and the hydraulic oil in the hydraulic cylinder 1b can build up pressure to push the valve core X of the reversing valve to act. That is, by changing the time of blocking the oil inlet and outlet holes 1c, the action time of the reversing valve can be changed, so that the injection timing is automatically adjusted with the speed of the diesel engine.

[0050] In the prior art, conventional fuel injection is a one-time injection, in which the fuel is atomized and mixed with the compressed air in the cylinder for combustion. Since the fuel has strong penetration during injection, the one-time injection will spray the fuel into the space outside the cylinder, and less fuel will be mixed near the center of the cylinder. The fuel in this cylinder is mixed unevenly, with more mixed at the periphery and thinner near the center. This results in an uneven fuel mixture concentration, which affects the combustion effect of the diesel engine. In view of the above shortcomings, the head of the plunger 32 of the present invention is also processed with an annular injection groove for realizing the sequential injection of high-pressure fuel in batches.

[0051] From the present invention Figures 14 to 19 It can be seen that the head of the plunger 32 is processed with two annular injection grooves that can make the high-pressure fuel be injected three times in sequence, and a lower annular oil groove 32c located below the annular injection grooves; so that the fuel can be injected once at a small load; at an intermediate load, it is injected twice; at a larger load, it is injected three times. The two annular injection grooves include a first annular injection groove 32a located at the top and a second annular injection groove 32b located at the bottom, and the lower annular oil groove 32c is located below the second annular injection groove 32b; the head of the plunger 32 is formed with an oblique cut oil groove 32d connected to the top surface of the plunger 32; the first annular injection groove 32a, the second annular injection groove 32b and the lower annular oil groove 32c are all connected to the oblique cut oil groove 32d.

[0052] The plunger sleeve 31 of the present invention is axially through-machined with a plunger sleeve cavity, and the plunger 32 is slidably and rotatably arranged in the plunger sleeve cavity of the plunger sleeve 31. The outer peripheral surface of the plunger sleeve 31 is formed with an annular fuel channel 31a connected to the fuel supply pipe, and the annular fuel channel 31a is machined with a fuel inlet hole 31b radially connecting the annular fuel channel 31a and the plunger sleeve cavity.

[0053] The present invention adopts a split injection method. A larger amount of fuel is injected during the first injection, which can reach 50-60% of the injection amount. It is injected to the periphery of the cylinder to meet the state of large peripheral space and more compressed air. After the first injection, the fuel starts to burn. After the pressure in the cylinder increases, the second injection begins. Since the pressure in the cylinder has increased, the penetration of the fuel injection is reduced, and the fuel can only be injected to the middle position of the cylinder. The amount of fuel injected in the second injection accounts for about 30-40% of the total injection amount. After the second injection is completed and starts to burn, the third injection is performed. Due to the combustion of the first two injections, the pressure in the cylinder is further increased, and the penetration after the fuel injection is further reduced. The third injection can only be injected near the center of the cylinder to mix with the compressed air in the center of the cylinder. Since the space in the center of the cylinder is small, the amount of fuel injected cannot be too much, and the third injection is only about 10% of the total amount of fuel injection.

[0054] The use of a phased sequential injection method can maximize the mixing of compressed air and fuel in the cylinder, avoid the problem of uneven concentration of air and fuel mixture in one injection, make the combustion more complete, and increase the fuel utilization rate; phased sequential injection, the injected fuel is burned three times, which can reduce the combustion pressure in the cylinder, lower the maximum combustion temperature in the cylinder, reduce the formation of NOx, reduce NOx emissions, and is beneficial to protecting the environment.

[0055] In order to realize the sequential injection, the present invention processes two annular injection grooves on the head of the plunger 32 of the high pressure oil pump 2. When the plunger 32 of the high pressure oil pump 2 is pulled to the lowest position by the power piston 4, as shown in FIG. Fig. 9 As shown, at this time, the plunger sleeve cavity (i.e., the oil cavity) on the top surface of the plunger 32 is connected to the fuel inlet hole 31b, and fuel begins to be filled.

[0056] When the power piston 4 moves upward, it pushes the high-pressure oil pump plunger 32 upward. When the upper edge of the plunger 32 covers the fuel inlet hole 31b of the plunger sleeve 31, the high-pressure oil pump 2 performs the first injection. Fig.14 shown.

[0057] When the plunger 32 of the high-pressure oil pump 2 moves upward to the first annular injection groove 32a and the fuel inlet hole 31b, the oil chamber on the top surface of the plunger 32 is connected to the fuel inlet hole 31b through the oblique cut oil groove 32d and the first annular injection groove 32a, the pressure decreases, and the first injection ends. Fig.15 shown.

[0058] When the plunger 32 of the high pressure oil pump continues to move upward, the plunger surface at the lower part of the first annular injection groove 32a partially covers the fuel inlet hole 31b, and the high pressure oil pump 2 starts the second injection. Fig.16 shown.

[0059] When the plunger 32 of the high-pressure oil pump moves upward to the second annular injection groove 32b and the fuel inlet hole 31b, the oil cavity on the top surface of the plunger 32 is connected to the fuel inlet hole 31b through the oblique cut oil groove 32d and the second annular injection groove 32b, the pressure decreases, and the second injection ends. Fig.17 shown.

[0060] When the plunger 32 of the high-pressure fuel pump 2 continues to move upward, the plunger surface at the lower part of the second annular fuel injection groove 32b partially covers the fuel inlet hole 31b, and the high-pressure fuel pump 2 starts to inject fuel for the third time. Fig.18 shown.

[0061] When the plunger 32 of the high-pressure oil pump 2 moves upward to the highest point, the lower annular oil groove 32c at the bottom of the plunger 32 is aligned with the fuel inlet hole 31b, and the oil chamber on the top surface of the plunger 32 is connected with the fuel inlet hole 31b through the oblique cut oil groove 32d and the lower annular oil groove 32c. At this time, the fuel pressure in the oil chamber is reduced to the same as the fuel pressure in the fuel inlet hole 31b, and the injection is terminated. Fig.19 shown.

[0062] The power oil pump, the reversing valve and the injection timing adjustment sleeve rack 6 of the present invention together constitute the injection timing adjustment and injection control mechanism; the hydraulic piston 5 is composed of a tappet 51, a roller 52, a roller pin 53, an injection timing adjustment gear sleeve 54, an oil storage piston 55 and a return spring 56. The roller pin 53 is inserted into the pin hole at the lower end of the tappet 51, and the roller 52 is rotatably mounted on the roller pin 53, and the roller 52 is in rolling contact with the cam of the diesel engine; the oil storage piston 55 is slidably arranged at the upper end of the oil storage cavity 5a processed by the tappet 51, and the return spring 56 is elastically pressed into the oil storage cavity 5a through the oil storage piston 55; the injection timing adjustment gear sleeve 54 can be rotatably inserted on the tappet 51, and the outer surface of the injection timing adjustment gear sleeve 54 is processed with a gear 54a meshing with the injection timing adjustment sleeve rack 6. The injection timing adjustment gear sleeve 54 is machined with a gear sleeve oblique cut 54b for changing the time of covering the inlet and outlet oil holes 1c. The relative position of the gear sleeve oblique cut 54b and the inlet and outlet oil holes 1c on the hydraulic cylinder 1b changes with the rotation of the injection timing adjustment gear sleeve 54; the high-pressure oil pump seat 1 is machined with a pressure oil channel 1d connected to the hydraulic cylinder 1b for pushing the valve core X of the reversing valve to move.

[0063] The injection timing adjustment gear sleeve 54 of the present invention is processed with a gear 54a, and the gear 54a is meshed with the injection timing adjustment sleeve rack 6. In this way, when the injection timing adjustment sleeve rack 6 is connected to the diesel engine speed adjustment mechanism, as the diesel engine speed adjustment mechanism is synchronously operated, the injection timing adjustment sleeve rack 6 can pull the injection timing adjustment gear sleeve 54 to rotate along the tappet 51.

[0064] The working principle of the injection timing adjustment and injection control mechanism is: the hydraulic piston 5 and the hydraulic cylinder 1b form a power oil pump, and the roller 52 of the hydraulic piston 5 moves up and down along the cam of the diesel engine. When the hydraulic piston 5 moves upward, it pushes the hydraulic oil into the reversing valve, pushing the valve core X of the reversing valve to move; when the hydraulic piston 5 moves downward, the hydraulic piston 5 and the hydraulic cylinder 1b form a low pressure, and the right end face of the valve core X of the reversing valve moves in the opposite direction under the action of the hydraulic oil. The relative position of the gear sleeve oblique cut 54b on the injection timing adjustment gear sleeve 54 and the oil inlet and outlet holes 1c on the hydraulic cylinder 1b changes with the rotation of the injection timing adjustment gear sleeve 54. When the gear sleeve oblique cut 54b of the injection timing adjustment gear sleeve 54 completely covers the oil inlet and outlet holes 1c, pressure is formed in the hydraulic cylinder 1b to push the valve core X of the reversing valve to move. The time when the gear sleeve bevel cutout 54b on the injection timing adjustment gear sleeve 54 covers the oil inlet and outlet holes 1c determines the size of the diesel engine's injection angle. When the diesel engine speed is low, the oil inlet and outlet holes 1c are covered later, that is, the injection is late and the injection angle is small; when the diesel engine speed is high, the injection timing adjustment gear sleeve 54 rotates under the drag of the injection timing adjustment sleeve rack 6, covering the oil inlet and outlet holes 1c earlier, that is, the injection time is advanced and the injection angle becomes larger. The oil inlet and outlet holes 1c on the hydraulic cylinder 1b are connected to the low-pressure oil channel. Only when the oil inlet and outlet holes 1c are covered will pressure oil be formed, and the valve core X of the reversing valve can be pushed to move.

[0065] As the injection timing adjustment gear sleeve 54 of the hydraulic piston 5 rotates with the pull of the injection timing adjustment sleeve rack 6, the hydraulic oil displacement will change greatly. When the diesel engine is at a low speed, the injection timing adjustment gear sleeve 54 covers the oil inlet and outlet holes 1c later, and the corresponding hydraulic oil discharged is relatively small; when the diesel engine speed is high, the injection timing adjustment gear sleeve 54 rotates to a position that covers the oil inlet and outlet holes 1c earlier, and the corresponding hydraulic oil discharged is more. However, the amount of oil required to push the valve core X of the reversing valve to move remains unchanged. In order to adapt to the change in the displacement of the hydraulic piston 5. The present invention processes an oil storage chamber 5a at the center of the tappet 51, and the oil storage chamber 5a forms an oil storage space with the oil storage piston 55 and the return spring 56. When the amount of oil discharged by the hydraulic piston 5 is greater than the amount of oil required by the reversing valve, the excess oil squeezes the oil storage piston 55 and the return spring 56 downward, and the increased space stores the excess hydraulic oil. When the hydraulic piston 5 moves downward, the hydraulic oil in the oil storage space has a certain pressure due to the presence of the return spring 56, which can release the hydraulic oil in the oil storage chamber 5a and push the oil storage piston 55 to return to its original position.

[0066] The power piston 4 of the present invention is connected to the plunger 32 so as to be relatively rotatable. The upper end of the plug rod 41 of the power piston 4 is processed with an annular snap-in groove 41a with a radial snap-in inlet, and the lower end of the plunger 32 is formed with an annular snap-in protrusion 321 that can be snapped into the annular snap-in groove 41a in an axially anti-slip manner. The snap-in inlet can make the plunger 32 easily snap into the annular snap-in groove 41a, making disassembly and installation more convenient. After the plunger 32 is snapped into the annular snap-in groove 41a, the plunger 32 can rotate freely relative to the power piston 4. A plunger rack 322 is formed at the lower part of the plunger 32, and a high-pressure oil pump oil adjustment rack 9 is installed on the high-pressure oil pump 1. The high-pressure oil pump oil adjustment rack 9 is connected to the adjustment mechanism of the high-pressure oil pump and acts synchronously with the adjustment mechanism of the high-pressure oil pump. The high-pressure oil pump oil regulating rack 9 is meshed with the plunger rack 322, and the adjustment mechanism of the high-pressure oil pump drives the high-pressure oil pump oil regulating rack 9. The high-pressure oil pump oil regulating rack 9 rotates by pulling the plunger 32, changing the position of the beveled oil groove 32d and the fuel inlet hole 31b, thereby changing the fuel inlet.

[0067] By the present invention Figure 1 and Figure 2 It can be seen that the oil return pipe 8 of the present invention is equipped with an overflow valve F1, and the oil inlet pipe is equipped with a pressure reducing valve F2 and a pressure stabilizing valve F3.

[0068] The up and down movement of the power piston 4 of the present invention is achieved by the push of hydraulic oil. The hydraulic oil discharged by the hydraulic piston 5 pushes the reversing valve to control the inlet and outlet of the hydraulic oil in the oil inlet pipe.

[0069] The oil return control of the rod chamber at the upper end of the power piston of the present invention is as follows:

[0070] When the hydraulic piston 5 moves upward under the push of the diesel engine cam and covers the oil inlet and outlet holes 1c on the hydraulic cylinder 1b, a closed oil chamber is formed between the hydraulic piston 5 and the hydraulic cylinder 1b and the pressure oil passage 1d connected to the reversing valve. The hydraulic oil in the hydraulic cylinder 1b builds up pressure, and the hydraulic piston 5 continues to move upward. The pressure of the hydraulic oil in the hydraulic cylinder 1b pushes the reversing valve core X to move right, so that the rod chamber at the upper end of the power piston 4 is connected to the oil return pipe 8, and the hydraulic oil in the rod chamber flows back to the oil return pipe 8.

[0071] The oil inlet control of the rod chamber at the upper end of the power piston 4 is:

[0072] When the hydraulic piston 5 moves downward along with the diesel engine cam, the reversing valve core X moves leftward under the push of the hydraulic oil at the right end, and the high-pressure hydraulic oil in the oil inlet pipe 72 of the power piston is connected with the rod chamber at the upper end of the power piston 4 through the reversing valve. The hydraulic oil enters the rod chamber at the upper end of the power piston 4, and the power piston 4 moves downward under the action of the high-pressure oil.

[0073] The plunger 32 of the present invention can rotate freely, ensuring that the plunger 32 supplies different injection amounts according to different loads. The plunger 32 of the high-pressure oil pump 2 is driven by the power piston 4 to work, relying on the up and down movement of the power piston 4 to provide the high-pressure oil pump with injection power and fuel inlet. Since the lower surface of the plug body 42 of the power piston 4 is subjected to the same hydraulic thrust at different speeds of the diesel engine, the high-pressure oil pump 2 has the same injection pressure at various speeds, and the injected fuel has the same atomization effect. Due to the greater pressure borne by the lower surface of the plug body 42 of the power piston 4, the high-pressure oil pump 2 can spray with greater force, and the injection pressure can be increased to more than 200MPa according to the needs of the diesel engine, and can reach 250MPa, which is much greater than the fuel injection pressure of the high-pressure common rail system.

[0074] The working roadmap of the present invention is:

[0075] 1. A power oil pump is formed by the hydraulic piston 5 and the hydraulic cylinder 1b at the lower part of the high-pressure oil pump seat 1, and the reversing valve is controlled to realize the up and down movement of the power piston 4, and further realize the fuel injection and oil inlet of the fuel high-pressure oil pump;

[0076] 2. The injection timing adjustment gear sleeve 54 on the hydraulic piston 5 is rotated by the linear motion of the injection timing adjustment sleeve rack connected to the diesel engine speed adjustment mechanism, so as to change the time of shielding the oil inlet and outlet holes on the wall of the hydraulic cylinder 1b, change the action time of the reversing valve, and then change the injection angle, so as to realize the automatic adjustment of the injection timing with the diesel engine speed;

[0077] 3. The device adopts full hydraulic control mode. The whole device uses the same hydraulic system. Different pressures are obtained through the pressure reducing valve, pressure stabilizing valve and overflow valve to control the up and down movement of the power piston 4 and the reversing valve reset;

[0078] 4. The fuel high-pressure oil pump 2 is connected to the power piston 4 and moves synchronously with the power piston 4 to realize the oil inlet and fuel injection of the high-pressure oil pump 2;

[0079] 5. Two annular injection grooves are processed on the injection part of the plunger 32 of the fuel high-pressure fuel pump 2 to realize the injection sequence, so that the original one-time injection is changed to three injections, achieving the effect of zoned combustion and making the compressed air and atomized fuel mixed more evenly.

[0080] 6. Since the power piston 4 is subjected to the same pressure during the entire injection process, the fuel high-pressure oil pump 2 can use the same injection pressure at different speeds, that is, have the same atomization effect, avoiding poor atomization at low speeds.

[0081] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A diesel engine fuel injection device with variable injection timing, sequence and high pressure constant pressure, comprising a high pressure oil pump seat (1) with a high pressure oil pump (2) mounted on the upper end, a plunger pair consisting of a plunger sleeve (31) and a plunger (32) mounted in the high pressure oil pump (2), an oil outlet connector (T) mounted on the upper end of the high pressure oil pump (2), an oil outlet valve (F) cooperating with the plunger pair to start injection mounted in the oil outlet connector (T), characterized in that: The high-pressure oil pump seat (1) is processed with a power piston cylinder (1a) and a hydraulic cylinder (1b) in an upper and lower structure. The power piston cylinder (1a) is equipped with an oil injection driving mechanism that is driven by hydraulic oil to drive the plunger (32) to move up and down. The oil injection driving mechanism includes a power piston (4) whose lower end surface can have the same hydraulic thrust at different speeds of the diesel engine to achieve high-pressure constant-pressure injection. The upper end of the plug rod (41) of the power piston (4) is connected to the lower end of the plunger (32); The high-pressure oil pump seat (1) is provided with an oil inlet pipe and an oil return pipe (8) for supplying hydraulic oil to the power piston (4) for up and down movement through a reversing valve. A hydraulic piston (5) is slidably provided in the hydraulic cylinder (1b). The hydraulic piston (5) and the hydraulic cylinder (1b) together constitute a power oil pump for changing the oil supply direction by pushing the valve core (X) of the reversing valve to move left and right by hydraulic oil. The hydraulic piston (5) moves up and down under the push of the diesel engine cam. The hydraulic cylinder (1b) is provided with hydraulic oil inlet and outlet holes (1c). The hydraulic piston (5) is meshed with an injection timing adjustment sleeve rack (6) connected to a diesel engine speed adjustment mechanism and moving synchronously with the diesel engine speed adjustment mechanism. The injection timing adjustment sleeve rack (6) changes the action time of the reversing valve by pulling the hydraulic piston (5) to rotate and change the time of covering the inlet and outlet holes (1c), so that the injection timing is automatically adjusted with the diesel engine speed. The head of the plunger (32) is processed with an annular injection groove for realizing the sequential injection of high-pressure fuel in batches. The power oil pump, the reversing valve and the injection timing adjustment sleeve rack (6) together constitute an injection timing adjustment and injection control mechanism; the hydraulic piston (5) is composed of a tappet (51), a roller (52), a roller pin (53), an injection timing adjustment gear sleeve (54), an oil storage piston (55) and a return spring (56); the roller pin (53) is inserted into the pin hole at the lower end of the tappet (51), and the roller (52) is rotatably mounted on the roller pin (53). ) is in rolling contact with the cam of the diesel engine; the oil storage piston (55) is slidably arranged at the upper end of the oil storage chamber (5a) processed by the tappet (51), and the return spring (56) is elastically pressed into the oil storage chamber (5a) through the oil storage piston (55); the injection timing adjustment gear sleeve (54) is rotatably mounted on the tappet (51), and the outer surface of the injection timing adjustment gear sleeve (54) is processed with a gear (54a) meshing with the injection timing adjustment sleeve rack (6); The oil return control of the rod chamber at the upper end of the power piston is as follows: when the hydraulic piston (5) moves upward under the push of the diesel engine cam to cover the oil inlet and outlet holes (1c) on the hydraulic cylinder (1b), a closed oil chamber is formed between the hydraulic piston (5), the hydraulic cylinder (1b) and the pressure oil passage (1d) connected to the reversing valve; the hydraulic oil in the hydraulic cylinder (1b) builds up pressure, the hydraulic piston (5) continues to move upward, and the pressure of the hydraulic oil in the hydraulic cylinder (1b) pushes the reversing valve core (X) to move rightward, so that the upper end of the power piston (4) The rod chamber is connected to the oil return pipe (8), and the hydraulic oil in the rod chamber flows back to the oil return pipe (8); the oil inlet control of the rod chamber at the upper end of the power piston (4) is as follows: when the hydraulic piston (5) moves downward along with the diesel engine cam, the spool of the reversing valve (X) moves leftward under the push of the hydraulic oil at the right end, and the high-pressure hydraulic oil in the oil inlet pipe 72 of the power piston is connected to the rod chamber at the upper end of the power piston (4) through the reversing valve, and the hydraulic oil enters the rod chamber at the upper end of the power piston (4), and the power piston (4) moves downward under the action of the high-pressure oil.

2. The diesel engine fuel variable injection timing, sequence and high pressure constant pressure injection device according to claim 1 is characterized in that: The injection timing adjustment gear sleeve (54) is processed with a gear sleeve bevel cut (54b) for changing the time of covering the oil inlet and outlet holes (1c); the relative position of the gear sleeve bevel cut (54b) and the oil inlet and outlet holes (1c) on the hydraulic cylinder (1b) changes with the rotation of the injection timing adjustment gear sleeve (54); and the high-pressure oil pump seat (1) is processed with a pressure oil channel (1d) connected to the hydraulic cylinder (1b) for driving the valve core (X) of the reversing valve.

3. The diesel engine fuel variable injection timing, sequence and high pressure constant pressure injection device according to claim 2 is characterized by: A plug body (42) is formed at the bottom of the plug rod (41) of the power piston (4), and a sealing annular groove (4a) is processed on the plug body (42), and a sealing ring (M) is installed in the sealing annular groove (4a) for sealing; the plug body (42) divides the power piston cylinder (1a) into a rod chamber located above the plug body (42) and a rodless chamber located below the plug body (42); the oil inlet pipe includes an upper power piston oil inlet pipe (71) connected to the rodless chamber of the power piston cylinder (1a) via a reversing valve and a lower power piston oil inlet pipe (72) connected to the rod chamber of the power piston cylinder (1a) via a reversing valve.

4. The diesel engine fuel variable injection timing, sequence and high pressure constant pressure injection device according to claim 3 is characterized by: The power piston (4) and the plunger (32) are connected to each other so as to be relatively rotatable. The upper end of the plug rod (41) of the power piston (4) is processed with an annular snap-in groove (41a) with a radial snap-in entrance, and the lower end of the plunger (32) is formed with an annular snap-in protrusion (321) that can be snapped into the annular snap-in groove (41a) in an axially anti-slip manner.

5. The diesel engine fuel variable injection timing, sequence and high pressure constant pressure injection device according to claim 4, characterized in that: The outer peripheral surface of the plunger sleeve (31) is formed with an annular fuel groove (31a) connected to the fuel supply pipe, and the annular fuel groove (31a) is processed with a fuel inlet hole (31b) radially connecting the annular fuel groove (31a) and the sleeve cavity of the plunger sleeve (31); the plunger (32) is slidably arranged in the sleeve cavity of the plunger sleeve (31).

6. The diesel engine fuel variable injection timing, sequence and high pressure constant pressure injection device according to claim 5, characterized in that: The head of the plunger (32) is processed with two annular oil injection grooves that can allow high-pressure fuel to be injected three times in sequence, and a lower annular oil groove (32c) located below the annular oil injection grooves; the two annular oil injection grooves include a first annular oil injection groove (32a) located above and a second annular oil injection groove (32b) located below, and the lower annular oil groove (32c) is located below the second annular oil injection groove (32b); the head of the plunger (32) is formed with an oblique cut oil groove (32d) connected to the top surface of the plunger (32); the first annular oil injection groove (32a), the second annular oil injection groove (32b) and the lower annular oil groove (32c) are all connected to the oblique cut oil groove (32d).

7. The diesel engine fuel variable injection timing, sequence and high pressure constant pressure injection device according to claim 6, characterized in that: A plunger rack (322) is formed at the lower part of the plunger (32), and a high-pressure oil pump oil regulating rack (9) is installed on the high-pressure oil pump (2) and meshes with the plunger rack (322) to change the position of the beveled oil groove (32d) and the fuel inlet hole (31b) by pulling the plunger (32) to rotate.

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